Pi-heptomino (or pi; sometimes called blasting cap at MIT after its shape at generation 1[1]) is a common heptomino that stabilizes at generation 173, leaving behind six blocks, five blinkers and two ponds. The name "pi" is also applied to some slight variations of this object that follow that same evolutionary sequence – in a pi ship, for example, the pi-heptomino itself never actually arises. Forms that are synonymous with the pi-heptomino are displayed below.